PURPOSE: To lengthen the reach of blown supply air and make the temperature distribution uniform in a room by disposing a rotary semicylindrical flap above each rectangular air outlet separately, and delivering temperature-conditioned air alternatingly from two of the four air outlets.

CONSTITUTION: A rotary flap 7a, 7b, 7c, 7d is respectively disposed to air outlet 3a, 3b, 3c, 3d arranged on four sides, and opposing flaps 7a, 7c and 7b, 7d are synchronized in their rotary cycle, and the rotary cycle of the adjacent flaps is phasse-staggered by 180°. By alternatingly opening and closing the outlets 3a, 3c, and 3b, 3d on the four sides, the speed of the temperature-conditioned air passing through the air outlets can be increased to allow a substantially longer reach of the temperature-controlled air supply. Moreover, on account of the semicylindrical rotary flaps 7aW7d, the wind direction can automatically be changed from directly under the indoor unit to the outer perimeter of room, and so, the temperature can be made uniform from corner to corner of the room, offering a comfortable air conditioned space.